The Abundances of Light and Fe Group Elements in LS 5130, A B2 IV Star Located 3 kpc from the Galactic Center

LS 5130 is a sharp-lined B2 IV star located only 3 kpc from the galactic center. Many studies have concluded that the abundances of the light and Fe group elements are larger than solar values in the inner region of our galaxy. We have obtained high-resolution FUV spectra of several early B stars with HST/COS to determine the extent to which main-sequence B stars confirm the large abundances. We supplement the HST spectra with high-resolution optical spectra from the FEROS spectrograph located on the ESO/MPG 2.2-m telescope at La Silla, Chile. The FUV and optical spectra were analyzed with the Hubeny/Lanz NLTE spectrum synthesis programs TLUSTY/SYNSPEC. Early B stars have preserved a good record of the abundances of the light, Fe-peak, and heavier elements in the interstellar cloud from which they were formed and serve as good tracers of chemical evolution in a galaxy. Our study finds that the chemical abundances in LS 5130 tend to be in the range of solar to 0.2 dex above solar values. We discuss factors such as continuum placement and microturbulence that introduce uncertainties. We also discuss how the abundances of especially the Fe group elements (for which spectral lines, except for 1-2 multiplets of Fe III, are found only in the UV) can reveal the types of supernovae that recently have enriched the ISM. The authors are grateful for support from HST grant HST-GO-15869.